1. Field of the Invention
The present invention relates to the art of resetting a printed-wiring-board supporting device which supports a printed wiring board (PWB), and particularly relates to the art of shortening a time needed to reset the PWB supporting device. A PWB with electric components (e.g., electronic components) being mounted thereon should be called as a printed circuit board (PCB) but, in the present specification, a PCB is also referred to as a PWB, for avoiding complexity.
2. Discussion of Related Art
Generally, a PWB includes a thin substrate formed of an electrically insulating material such as a synthetic resin, and a circuit pattern formed of an electrically conductive material on the thin substrate. Thus, the PWB has flexibility. Therefore, when electric components (ECs) are mounted on the PWB, or when an adhesive or a creamed solder is applied to the PWB for mounting of ECs, the PWB cannot maintain an accurate flatness, unless a back surface of the PWB is supported at a considerably large number of points.
To solve this problem, Japanese Patent Document No. 7-15189 teaches applying a negative pressure or suction to a PWB and thereby holding the same. More specifically described, the document discloses a PWB holding device including a base plate and a plurality of holding pins. The base plate has a plurality of negative-pressure-supply holes each of which opens in an upper surface thereof and is connected via a negative-pressure passage formed therein to a negative-pressure-supply source. Each of the holding pins includes an elongate pin portion and a container-like seat portion, and the pin portion has a passage which is formed therethrough in an axial direction thereof and is communicated with an inner space of the seat portion. Each holding pin is attached to the upper surface of the base plate, such that a lower-end surface of the seat portion thereof is held in close contact with a portion of the upper surface that surrounds the opening of one negative-pressure-supply hole. In this state, the inner passage of the pin portion is communicated with the negative-pressure-supply hole via the inner space of the seat portion, so that negative pressure is supplied to the inner passage and is applied to a lower or back surface of a PWB to support the same. Thus, the PWB holding device is a PWB supporting device which has the function of sucking and holding a PWB.
The holding pins support the back surface of the PWB that is opposite to the front surface for which an operation, such as mounting of ECs, is performed. However, the holding pins must not engage uneven portions of the back surface of the PWB itself or the ECs mounted on the back surface. Therefore, the holding pins must be engaged with only limited portions of the back surface of the PWB and, depending upon those limited portions of the back surface, the holding pins must be attached to only limited portions of the upper surface of the base plate. Thus, the holding pins are attached to selected ones of the negative-pressure-supply holes of the base plate, and the remaining supply holes to which the holding pins are not attached are closed with respective caps to avoid the leakage of negative pressure.
However, conventionally it is an operator who sets the holding pins on the base plate and attaches the caps to the negative-pressure-supply holes free of the holding pins, and accordingly it takes a long time to reset the PWB holding device. When a current sort of PWBs are changed to a new sort of PWBs for each of which an operation is to be performed, the PWB holding device is reset by moving the holding pins from the current positions to new positions to support the new sort of PWBs. However, this resetting operation needs a long time.
This problem occurs to not only a PWB supporting device which includes holding pins each for applying negative pressure to a PWB and thereby holding the same but also a PWB supporting device which does not have the function of applying negative pressure to a back surface of a PWB and thereby holding the same but includes closing-pins each for supporting, at a support surface thereof, a back surface of a PWB and thereby supporting the same. The latter PWB supporting device does not require the operator to attach caps to negative-pressure-supply holes, but it needs a long time for the operator to set the closing-pins at respective prescribed positions. Thus, it takes a long time to reset the latter PWB supporting device as well.
The present invention provides a PWB-supporting-device resetting apparatus, a PWB-holding-device resetting apparatus, a PWB-relating-operation performing system, and a PWB-supporting-device resetting method that have each feature described below. The following features are described, like claims, in respective paragraphs that are given respective sequential numbers. Any feature that includes another feature shall do so by referring to the number given to the latter feature. However, the following features and the appropriate combinations thereof are just examples to which the technical features, and the combinations thereof, described in the specification are by no means limited. In addition, in the case where one feature recites a plurality of items, it is not essentially required that all of those items be simultaneously employed in the one feature. That is, it is possible to select and employ only a portion (one, two, . . . , but not all) of those items.
(1) According to a first feature of the present invention, there is provided an apparatus for automatically resetting a printed-wiring-board supporting device including a supporting table and a plurality of supporting members which are set on a surface of the supporting table to support a back surface of a printed wiring board, the apparatus comprising a supporting member storing device in which the supporting members are stored; a holding head which can hold each of the supporting members; a moving device which moves at least one of the holding head, and each of the supporting table and the storing device, relative to the other of the holding head and the each of the supporting table and the storing device, in at least a direction parallel to the surface of the supporting table, so that the holding head takes a prescribed one of the supporting members from the storing device and sets the one supporting member at a prescribed setting position on the surface of the supporting table, and takes the one supporting member from the setting position and stores the one supporting member in the storing device; and a control device which controls the moving device.
According to this feature, each of the supporting members may be one which has at least the function of supporting the printed wiring board (PWB). Therefore, each supporting member may be either a holding member which supports the PWB while sucking and holding the same, or a simple member which just supports the PWB but does not have the sucking-and-holding function. In the former case, the PWB supporting device can be called a PWB holding device.
The automatic resetting apparatus according to this feature may be provided as part of a PWB-relating-operation performing system which includes an operation performing device that performs an operation for a front surface of a PWB supported by a PWB supporting device, so that the resetting apparatus may automatically reset the PWB supporting device inside the system. Alternatively, the present resetting apparatus may be provided independent of a PWB-relating-operation performing system, so that the resetting apparatus may automatically reset a PWB supporting device outside the system. In the former case, the operation performing device of the system and the automatic resetting apparatus may be supported by a common main frame, and the PWB supporting device may not be detached from the main frame. In the latter case, a main frame of the performing system and a main frame of the resetting apparatus are independent of each other, and the PWB supporting device is attached to, and detached from, each of the respective main frames of the system and the apparatus.
In order to reset the PWB supporting device, the moving device moves one of the holding head, and each of the supporting table and the storing device, relative to the other of the holding head and the each of the supporting table and the storing device, so that the holding head detaches the supporting members currently set on the supporting table, from the supporting table, and stores the detached supporting members in the storing device, and takes, from the storing device, the supporting members to be used to support the next PWB, and sets the taken supporting members on the supporting table. Thus, the detaching, storing, taking, and setting of the supporting members are automatically performed, that is, the resetting operation is performed in a short time without needing the help of an operator.
(2) According to a second feature of the present invention, there is provided an apparatus for automatically resetting a printed-wiring-board holding device including a holding table having a surface and a plurality of negative-pressure-supply holes opening in the surface, and additionally including a plurality of holding members each of which has a support surface and a negative-pressure passage formed therethrough and is set on the surface of the holding table to support, at the support surface thereof, a back surface of a printed wiring board, and apply a negative pressure supplied via the negative-pressure passage thereof from at least one of the negative-pressure-supply holes, to the back surface of the printed wiring board and thereby hold the board, the apparatus comprising a holding-member storing device in which the holding members are stored; a first holding head which can hold each of the holding members; a first moving device which moves at least one of the first holding head, and each of the holding table and the holding-member storing device, relative to the other of the first holding head and the each of the holding table and the holding-member storing device, in at least a direction parallel to the surface of the holding table, so that the first holding head takes a prescribed one of the holding members from the holding-member storing device and sets the one holding member at a prescribed setting position on the surface of the holding table, and takes the one holding member from the setting position and stores the one holding member in the holding-member storing device; a plurality of closing members each of which is set on the surface of the holding table and closes one of the negative-pressure-supply holes that is not communicated with the negative-pressure passages of any holding members; a closing-member storing device in which the closing members are stored; a second holding head which can hold each of the closing members; a second moving device which moves at least one of the second holding head, and each of the holding table and the closing-member storing device, relative to the other of the second holding head and the each of the holding table and the closing-member storing device, in at least a direction parallel to the surface of the holding table, so that the second holding head takes a prescribed one of the closing members from the closing-member storing device and sets the one closing member at a prescribed closing position on the surface of the holding table where the one closing member closes a prescribed one of the negative-pressure-supply holes that is not communicated with the negative-pressure passages of any holding members, and the second holding head takes the one closing member from the closing position and stores the one closing member in the closing-member storing device; and a control device which controls the first moving device so that the first holding head takes the one holding member from the holding-member storing device and sets the one holding member at the setting position, and takes the one holding member from the setting position and stores the one holding member in the holding-member storing device, and controls the second moving device so that the second holding head takes the one closing member from the closing-member storing device and sets the one closing member at the closing position, and takes the one closing member from the closing position and stores the one closing member in the closing-member storing device.
Like the automatic resetting apparatus according to the first feature (1), the automatic resetting apparatus according to this feature may be provided as part of a PWB-relating-operation performing system, or may be provided independent of a PWB-relating-operation performing system.
As described previously, the holding members can hold only limited areas of the back surface of the PWB. Therefore, the holding members are set at only respective setting positions corresponding to selected ones of the negative-pressure-supply holes provided in the holding table, and the closing members are set to close the negative-pressure-supply holes to which the holding members are not attached, thereby preventing the leakage of negative pressure. The automatic resetting apparatus according to this feature automatically sets the holding members and the closing members on the holding table and automatically stores the holding and closing members in the storing device. Thus, the PWB holding device that applies negative pressure to the PWB and thereby holds the same can be reset in a short time.
(3) According to a third feature of the present invention that includes the second feature (2), the second holding head is provided by the first holding head, and the second moving device is provided by the first moving device.
According to this feature, the automatic resetting apparatus can be constructed with ease and manufactured at low cost.
(4) According to a fourth feature of the present invention that includes the second or third feature (2) or (3), the closing-member storing device is provided by the holding-member storing device.
The holding-member storing device may be one which has a holding-member storing area and a closing-member storing area for storing the holding members and the closing members, respectively, separately from each other, or one which stores the holding members and the closing members in a mixed manner.
Alternatively, the closing-member storing device and the holding-member storing device may be provided independent of each other. However, according to the fourth feature (4), the single storing device stores both the holding and closing members, and accordingly the resetting apparatus enjoys a simplified construction. In addition, the distance of relative movement between the holding head and each of the storing device and the holding table can be reduced, which leads to shortening the time needed to perform the resetting operation.
(5) According to a fifth feature of the present invention that includes any one of the second to fourth features (2) to (4), the resetting apparatus further comprises a holding-table holding device which holds the holding table such that the holding table is detachable therefrom.
The present feature may be employed in the automatic PWB-supporting-device resetting apparatus according to the first feature (1).
The holding table may be attached to, and detached from, the holding-table holding device, either manually by an operator, or automatically by an attaching and detaching device.
In the case where an automatic resetting apparatus which is provided independent of a PWB-relating-operation performing system performs, outside the system, a plurality of resetting operations for a plurality of PWB holding devices, respectively, the PWB holding devices are sequentially attached to, and detached from, the automatic resetting apparatus. To this end, the holding-table holding device is employed to hold the holding table of each of the PWB holding devices. The present feature is effective in the case where the holding-table holding device has such a construction which assures that each holding table can be attached thereto and detached therefrom in a time shorter than a time needed by an automatic resetting apparatus employed by a PWB-relating-operation performing system to perform each automatic resetting operation. In the last case, the advantage that each automatic resetting operation can be performed in a reduced time is not damaged.
(6) According to a sixth feature of the present invention, there is provided a system for performing an operation relating a printed wiring board, comprising a main frame; a printed-wiring-board supporting device including a supporting table provided on the main frame, and a plurality of supporting members set on a surface of the supporting table to support a back surface of the printed wiring board; an operation performing device which is provided on the main frame and performs an operation for a front surface of the printed wiring board supported by the printed-wiring-board supporting device; a supporting-member storing device in which the supporting members are stored; a holding head which can hold each of the supporting members; a moving device which moves at least one of the holding head, and each of the supporting table and the storing device, relative to the other of the holding head and the each of the supporting table and the storing device, in at least a direction parallel to the surface of the supporting table, so that the holding head takes a prescribed one of the supporting members from the storing device and sets the one supporting member at a prescribed setting position on the surface of the supporting table, and takes the one supporting member from the setting position and stores the one supporting member in the storing device; and a control device which controls the moving device.
The operation performing device may be an electric-component mounting device which mounts electric components (ECs) on a front surface of PWB; a screen printing machine which screen-prints creamed solder on a front surface of a PWB; a highly-viscous-fluid applying device which sequentially applies a highly viscous fluid, such as adhesive, to a single spot, or plural spots, on a front surface of each of PWBs; or an electric-circuit inspecting device which inspects an electric circuit formed on a front surface of a PWB.
According to this feature, the PWB supporting device is automatically reset inside the PWB-relating-operation performing system.
(7) According to a seventh feature of the present invention, there is provided a system for performing an operation relating a printed wiring board, comprising a main frame; a printed-wiring-board holding device which is provided on the main frame, and includes a holding table having a surface and a plurality of negative-pressure-supply holes opening in the surface, and additionally includes a plurality of holding members each of which has a support surface, a bottom surface for close contact with the surface of the holding table, and a negative-pressure passage formed therethrough, and is set on the surface of the holding table such that the negative-pressure passage thereof is communicated with at least one of the negative-pressure-supply holes, so that the support surface of the each holding member supports the back surface of the printed wiring board and a negative pressure supplied via the negative-pressure passage from the at least one negative-pressure-supply hole is applied to the back surface of the board to hold the board; an operation performing device which is provided on the main frame and performs an operation for a front surface of the printed wiring board supported by the printed-wiring-board supporting device; a holding-member storing device which is provided on the main frame and in which the holding members are stored; a first holding head which can hold each of the holding members; a first moving device which moves at least one of the first holding head, and each of the holding table and the holding-member storing device, relative to the other of the first holding head and the each of the holding table and the holding-member storing device, in at least a direction parallel to the surface of the holding table, so that the first holding head takes a prescribed one of the holding members from the holding-member storing device and sets the one holding member at a prescribed setting position on the surface of the holding table, and takes the one holding member from the setting position and stores the one holding member in the holding-member storing device; a plurality of closing members each of which is set on the surface of the holding table and closes one of the negative-pressure-supply holes that is not communicated with the negative-pressure passages of any holding members; a closing-member storing device which is provided on the main frame and in which the closing members are stored; a second holding head which can hold each of the closing members; a second moving device which moves at least one of the second holding head, and each of the holding table and the closing-member storing device, relative to the other of the second holding head and the each of the holding table and the closing-member storing device, in at least a direction parallel to the surface of the holding table, so that the second holding head takes a prescribed one of the closing members from the closing-member storing device and sets the one closing member at a prescribed closing position on the surface of the holding table where the one closing member closes a prescribed one of the negative-pressure-supply holes that is not communicated with the negative-pressure passages of any holding members, and the second holding head takes the one closing member from the closing position and stores the one closing member in the closing-member storing device; and a control device which controls the first moving device so that the first holding head takes the one holding member from the holding-member storing device and sets the one holding member at the setting position, and takes the one holding member from the setting position and stores the one holding member in the holding-member storing device, and controls the second moving device so that the second holding head takes the one closing member from the closing-member storing device and sets the one closing member at the closing position, and takes the one closing member from the closing position and stores the one closing member in the closing-member storing device.
According to this feature, the PWB supporting device is automatically reset inside the PWB-relating-operation performing system.
(8) According to an eighth feature of the present invention that includes the seventh feature (7), the second holding head is provided by the first holding head, and the second moving device is provided by the first moving device.
(9) According to a ninth feature of the present invention that includes the seventh or eighth feature (7) or (8), the closing-member storing device is provided by the holding-member storing device.
(10) According to a tenth feature of the present invention that includes any one of the seventh to ninth features (7) to (9), the operation performing device comprises an operation performing head which performs the operation, and the first moving device moves at least one of the operation performing head and the printed-wiring-board supporting device, relative to the other of the operation performing head and the printed-wiring-board supporting device, in at least a direction parallel to the surface of the holding table, so that the operation performing head performs the operation.
According to this feature, the first moving device includes a portion that provides the relative movement between the operation performing head and the printed-wiring-board supporting device, in the direction parallel to the surface of the holding table.
(11) According to an eleventh feature of the present invention, there is provided a method of setting a printed-wiring-board supporting device of a printed-wiring-board-relating-operation performing system, the printed-wiring-board supporting device including a supporting table and a plurality of supporting members for being set on a surface of the supporting table to support a back surface of a printed wiring board, the printed-wiring-board-relating-operation performing system additionally including a main frame on which the supporting table is provided, and an operation performing device which is provided on the main frame and performs an operation for a front surface of the printed wiring board supported by the printed-wiring-board supporting device, the method comprising the steps of detaching the supporting table from the main frame of the system, setting, at a place outside the system, the supporting members on the supporting table, and attaching the supporting table on which the supporting members have been set, to the main frame of the system.
The supporting table may be attached to, and detached from, the main frame, either manually by an operator or automatically by an attaching and detaching device. In the state in which the supporting table, detached from the main frame of the PWB-relating-operation performing system, is placed outside the system, the supporting members may be set on the supporting table, either automatically by an apparatus having a construction similar to that of the automatic resetting apparatus according to the first feature (1), or manually by an operator.
The supporting table may be one which is used commonly for a plurality of sorts of PWBs, or one which is used exclusively for a single sort of PWBs. In the case where the supporting table is used commonly for a plurality of sorts of PWBs having different sizes, the supporting table should have such a size which assures that the supporting table can support the PWB having the largest size.
According to this feature, each of the supporting members may be a holding member which has the function of applying negative pressure to the PWB and thereby holding the PWB and supports the PWB by sucking and holding the same, or a simple supporting member which does not have the sucking-and-holding function.
According to this feature, the PWB holding device may be reset outside the PWB-relating-operation performing system, at an arbitrary timing, independent of the current state of the system. Therefore, while the operation is performed for the current PWBs, the supporting members can be set on the supporting table, so that the PWB holding device is reset and made read for supporting a new sort of PWBs which will replace the current sort of PWBs. Thus, the system can be reset by replacing the current PWB holding device with the thus reset PWB holding device, which leads to shortening the time needed to reset each PWB holding device to be used with the system. Thus, the efficiency of operation of the system can be improved.
(12) According to a twelfth feature of the present invention that includes the eleventh feature (11), the supporting table comprises a holding table having a plurality of negative-pressure-supply holes opening in the surface thereof, and the supporting members comprise a plurality of holding members each of which has a support surface, a bottom surface for close contact with the surface of the holding table, and a negative-pressure passage formed therethrough, the step of setting comprises setting, on the holding table detached from the main frame, each of the holding members such that the negative-pressure passage of the each holding member is communicated with at least one of the negative-pressure-supply holes of the holding table, and the step of attaching comprises closing, with at least one closing member, at least one of the negative-pressure-supply holes that is not communicated with the negative-pressure passages of any holding members and open in the surface of the holding table, and attaching the holding table with the holding members and the at least one closing member, to the main frame of the system.
Otherwise, the negative-pressure-supply holes of the holding table may be provided with respective opening and closing valves, as disclosed in one of Japanese patent applications which were filed on the same day by the assignee of the present application and from another of which the present application claims priority. In this case, each of the valves is opened by attaching a holding member to a corresponding one of the holes, and the holes to which the holding members are not attached remain closed by the valves. Thus, it is not needed to close, with closing members, the holes to which the holding members are not attached. The present method may be used to set this sort of PWB holding device. However, the present method is more effective in setting the PWB holding device of the sort recited in the twelfth feature (12), because it needs a longer time to set the same.